Installation for the surface treatment of parts

ABSTRACT

The invention relates to a machine for the surface processing of metal parts by immersion into at least one processing liquid contained in a processing tank comprising a plurality of tanks arranged in series and to a device for transferring the parts between the tanks, said tanks each including a rotary structure mounted on a rotation axis for receiving said parts submerged by a rotation movement of the rotary structures such that the air bubbles generated by the immersion of the parts are chased from the surfaces thereof, machine in which said rotation axis are rotatingly rigidly connected and driven by a common driving device. The tanks arranged in series may be contiguous and the rotation axes of the rotary structures may be aligned and assembled so as to form a common rotation axis extending through the entire machine. The rotation axis of the processing tank is electrically insulated from the other axis portions and connected to a power generator, in particular via a rotary connector arranged at one end of the axis. The downstream tank in the series is a steaming tank supplied with hot air. The machine is housed in a casing that comprises means for confining and reprocessing all the fluids from the machine.

The present invention belongs to the field of the treatment of surfaces of parts by immerging these parts in successive liquids contained in several treatment tanks and by transfer of the parts between these tanks, for example the electrochemical treatments of aluminum parts. As examples of such electrochemical treatments, the barrier anodizing or anodic passivation, the porous anodizing in acidic medium, the anodic dissolution, the hard or self-coloring anodizing, the electrolytic polishing and also electroplating such as nickel plating may be cited. The treating liquids may not only comprise electrolytes but also pre-treating liquids such as degreasing liquids, coloration liquids and rinsing liquids.

More particularly, the present invention provides an installation for the continuous surface treatment by immerging said parts in at least one treating liquid contained in a treatment tank, said installation including a plurality of tanks disposed in series, and a device for transferring the parts between the tanks, said tanks each comprising a rotary structure mounted on a rotation axle and able to receive said parts, the parts being immerged in said treatment liquid by a rotary movement of the rotary structure of the treatment tank selected in such a manner that air bubbles that may be formed during the immersion of said parts, are chased away from the surfaces of said parts.

The widest used installations for the treatment of the surface of aluminum parts are operated batchwise, i.e. by charges of a great volume. The document DE 2 119 401 describes the example of such an installation that comprises motorized carriages which move above several treatment tanks. The carriages are equipped with mobile arms for effecting vertical movements with large strokes for immerging important charges of objects to be treated and hanging from the mobile carriage, into successive tanks and to withdraw them therefrom. This kind of installation has several drawbacks:

-   -   when the parts to be treated are hollow, air bubbles or pockets         may appear at certain regions of their surface during the         immersion step into the is treatment liquid; this will produce         treatment irregularities and thus quality defects of the parts;     -   the volume of the tanks is important which leads to important         volumes of polluting liquid effluents to be reprocessed before         disposal;     -   the vertical movements of the charges above the tanks as well as         the important open surfaces of these tanks generate the         appearance of vapors and of droplets of active products,         especially acidic vapors, in the atmosphere of the treatment         unit, and this requires the installation of powerful and         expensive aeration and filtration systems for the treatment of         these gaseous effluents.

As a result, such treatment units can only be installed within a chemical plant that is specialized in surface treatments and processing and can therefore respect severe environmental security standards. The parts must thus be transported from the metallurgical factory where they were machined, to the factory where the surface treatment is effected, and then to the end user; high costs for packaging and transportation will have to be incurred.

In the international patent application No. WO 2006/084973 whose disclosure is incorporated into the present document by reference, the Applicant has already described an installation for the continuous surface treatment of parts, formed by a plurality of treatment tanks which each are equipped with a motorized rotary drum and whose axle of rotation is disposed horizontally in such a manner that the major portion of the drum is immerged in a treatment liquid contained in the corresponding tank. The parts to be treated, in particular when they are small, can before be put in place as small batches on supports that have the shape of boxes, for example those described in the patent application No. EP-A1-1 433 537 in the name of the Applicant, and these boxes are then transported by a conveyor system destined to feed each tank with parts to be treated and to transport the already treated parts downstream. The conveyor system has two parallel conveyor chains disposed on both sides of the upper portion of the tanks, the drum axes being disposed perpendicularly with respect to the two conveyor chains. Each tank is equipped with a device that transfers the boxes, one after the other, by means of a hydraulic cylinder by a horizontal push perpendicularly with respect to the axes of the conveyor chains, alternatively from one conveyor chain to the other, after the passage through the tank where they are temporarily fastened on slide rails disposed at the periphery of the rotary drum and where they undergo one or more rotations in the treatment liquid. Each rotary drum is driven via a cogwheel on the shaft of its motor which meshes with the periphery of a toothed disk or with a succession of pins disposed between two disks, these disks constituting a terminal face of the drum. The gear point is situated above the level of the liquid contained in the tank. The drums are supplied with electric current through these disks by means of sliding contact shoes which bear against these disks and are disposed in the tank above the level of the treatment liquid, in the manner described in the patent application No. WO 2007/122471 in the name of the Applicant. The current is then transmitted by the drum to the supports of the parts and then to the parts to be treated.

The rotations of the parts within the treating liquids eliminate the air bubbles or pockets from the surface of the parts and allow to obtain an excellent surface quality. The elimination of vertical displacements of the parts in an appreciable extent above the tanks reduces the overall space requirement of the installation and the formation of droplets and vapors and allows therefore to reduce the power of the air filtration systems in the treatment unit. However, since each tank constitutes an autonomous treatment sub-unit with its motorized drum and its transfer device, that installation uses a conveyor system and a transfer system that are relatively complicated, requiring an excellent synchronization of all these components. The installation also requires a driving device for each conveyor chain and several devices for the transfer between the chains and the tanks, and the costs of these devices is not negligible.

According to patent application No. WO 2008/035199 whose contents are incorporated into the present document by reference, the Applicant has described an installation for the continuous surface treatment of parts of the above depicted kind and composed of tanks containing motorized rotary drums that are similar to those described in the document No. WO 2006/084973, and regarding the tanks effecting an electrochemical treatment step as such, it comprises an electric supply system similar to that which is described in the document No. WO 2007/122471. Each tank, with its motorized drum, constitutes therefore only an autonomous sub-unit of the installation and mechanically independent from the other tanks. However, this installation uses a unique conveyor chain destined to supply each tank with parts to be treated, to collect the already treated parts and to transfer them into the next treatment station. The conveying of the parts is effected horizontally and parallel to the drum axes. The conveyor chain comprises horizontal transfer slide rails disposed between the tanks to which the slide rails of the rotary drums become to be aligned when the latter come to their uppermost position which emerges from the treatment liquid. Motorized carriages disposed above these slide rails make reciprocating movements on one guide rail that is parallel to the axes. Each carriage is equipped with an articulated rocker bar system comprising vertical arms allowing to push the boxes that are in their upper position and to drive them at each reciprocating cycle lengthwise on the slide rails of the drums and on the transfer slide rails. In this installation, it is intended to realize a rinsing of the parts by jets when they are positioned on a transfer slide rail between two tanks and/or after the last tank.

This installation has the same advantages as that which is described in the document No. WO 2006/084973 and simplifies the construction of the conveyor system. However, it uses as many driving motors as drums and at least as many articulated carriages as tanks, and the costs of these devices is not negligible. The installation also requires an excellent synchronization of the components since all displacements must be operated in a clocked manner.

It can be observed that, in the two installations mentioned above, the electric contact plots which are of graphite are wearing parts which are situated in the very interior of the electrolytic treatment tank, and that the contact zones of a drum disk with electric supply and with mechanical drives are exposed to treatment liquids, some of them being corrosive. It may also be noted that each driving motor of a drum is situated near the latter and adjacent to the upper opening of the tank and thus to the surface of the liquid which is contained therein. The cabinet of the motor is therefore exposed to vapors, in particular to corrosive vapors emerging from this tank. Maintenance costs must thus be incurred, in particular the replacement of contact parts and motor parts, and these costs are not negligible.

In the two installations for a continuous treatment described above, the conveyor chain transports the treated parts after the last rinsing step into a drying tunnel disposed downstream in these installations. The air coming from the drying tunnel is conducted into the air filtering system of the surface treating plant.

A first object of the present invention is to provide an installation of the kind defined above wherein the synchronization of the displacement of the parts can easier be realized.

Another object of the present invention is to provide an installation wherein the maintenance costs of the devices for realizing the supply with electric power to the parts to be treated as well as of the devices for rotating the part in the tanks are minimized.

A third object of the present invention is to provide an installation, especially an installation for anodizing aluminum parts, which can be run within a plant for the manufacture and machining of metal parts that is not yet equipped with devices for the treatment of effluents corresponding to standards required by a plant for electrochemical treatments.

A first object of the invention is a machine for the surface treatment of metallic parts by the immersion of said parts into at least one treatment liquid contained in a treatment tank, said machine including a plurality of tanks arranged in series, and a transfer device for the transfer of the parts between said tanks, said tanks each comprising a rotary structure mounted on a rotation axle and capable of receiving said parts, said parts being immerged in said treatment liquid by a rotational movement of the rotary structure of the treatment tank, selected in such a manner that air bubbles that may be formed during the immersion of said parts, are chased away from the surfaces of said parts, wherein said rotation axles of said rotary structures in the series of tanks of this machine are in rotary interlock condition and are driven by a common driving device.

The rotary coupling of the axles of the rotary structures and their drive by a unique device eliminates the difficulties of a synchronization of the movements of the rotary structures.

The invention has also as another object an installation for the surface treatment of metallic parts, comprising the machine having the above indicated characteristics, lodged in a container containing confinement a and retreating means for the fluids flowing out of said machine. Consequently, the container is a treatment unit that can be installed and operated within a plant that is not specialized for surface treatments.

In the machine according to the invention, the tanks in series may be contiguous. The rotation axles of said rotary structures of the tanks may be aligned and assembled in a manner to form a common rotation shaft or axle that traverses the whole machine.

In the machine according to the invention, the common driving device may be realized by means of an electric motor that drives directly the common rotary shaft or its segments that are put together with rotary interlocking by coupling. This driving motor may be disposed at a first extremity of the tanks series, especially at the downstream end.

Preferably, the rotary structure of the treatment tank which is intended to realize an electrochemical treatment step is connected to an electric generator via the rotation axle of the treatment tank, and said rotation axle of said treatment tank is electrically insulated from other segments of the machine axle. According to a mode of realization, the connection is implemented by means of a rotary connector which is mounted on said rotation axle of the treatment tank. According to a particular realization mode, the rotary connector is placed at a second extremity of the tank series.

In an installation according to the invention, where the common driving device, in particular the electric motor driving the axle of the rotary structures and/or the electric connector mounted on this axle, are disposed at the end portions of this axle, the lengths of these terminal portions may be selected such that they traverse the walls of the container in such a manner that the driving device or devices and/or the electric connection device will be placed outside the container. In such a configuration, these devices are not in contact with corrosive vapors, the frequency of replacement of parts is reduced and the maintenance of the devices is rendered easier.

If the machine according to the invention uses supports for holding the parts to be treated, for example supports in the form of boxes, said rotary structures are equipped with retaining devices capable of temporarily retaining these supports during the rotation movements of said rotary structures and capable of allowing a transfer movement of the supports between two rotation movements, the dimensions of said supports being adapted to said retaining device. Said supports have in turn fastening means adapted for holding and fixing said parts on said supports during said whole surface treatment.

According to a preferred realization mode, said retaining devices comprise slide rails which are parallel to the axles of said rotary structures, and each rotary structure of a tank is aligned with a rotary structure situated respectively immediately upstream and/or downstream, so as to allow the transfer of said supports over a tank and from one tank to the next one by sliding along said slide rails, under the action of transfer means.

The machine according to the invention comprises a transfer device disposed above the tanks and synchronized with the driving device of the machine axle, equipped with grasping elements for the supports which are in their upper position on said rotary structures, said transfer device effecting a simultaneous transfer movement of said supports in high position, each support in high position taking, under the influence of the transfer movement, the emplacement that was occupied before said transfer movement by the support in its high position immediately downstream.

According to a realization mode, said grasping elements comprise a pivoting shaft which extends over the series of tanks, and a group of arms mounted on said shaft, each arm bearing at its free end two pins distant and perpendicular with respect to the arm, the distance between these two pins of the same arm corresponding to the distance that separates two successive supports in upper position, the distance between two arms corresponding to the length of one said support. Preferably, the length of the arms is adjustable, and the height of the pins is also adjustable.

Preferably, the transfer device includes means for an alternating displacement between upstream and downstream of said grasping elements, and a particular realization mode comprises a group constituted by a driving pinion and a toothed rack, said pinion being fastened to a frame and a slide rail and meshing with said toothed rack that is fastened to a slider block, the stroke of said means for an alternating displacement being equal to the distance between two successive emplacements of the supports in high position.

The transfer device comprises also means for releasing said grasping elements which, according to a realization mode, include a motorized unit formed by a connecting rod and a crank for acting on said pivoting shaft in order to simultaneously activate and simultaneously release said grasping elements of all supports in upper position.

A particular object of the invention is a machine that is defined as described above and is destined for anodizing aluminum parts, comprising from upstream to downstream:

-   -   an oxidation tank for containing an electrolytic treatment         liquid, for example sulfuric acid, said oxidation tank         comprising one or more electrodes serving as cathode(s),         especially two cathodes disposed on both sides of the rotary         structure of the treatment tank, said rotary structure serving         as an anode,     -   a rinsing tank for containing a rinsing liquid, for example         water, and     -   a warming and drying tank for being fed with hot air.

Another, particular object of this invention is a machine that is defined as described above and is destined for the electrolytic nickel plating of steel parts, including from upstream to downstream:

-   -   a pickling tank for containing a pickling liquid;     -   a first rinsing tank for containing water;     -   a degreasing tank for containing an aqueous degreasing solution;     -   a second rinsing tank for containing water;     -   a depassivation tank for containing a sulfuric depassivation         liquid;     -   a third rinsing tank for containing water;     -   a nickel plating tank for the actual electroplating and destined         for containing a nickel sulfate solution and equipped with         electrode forming nickel plates, especially two anodes disposed         at both sides of the rotary structure of said nickel plating         tank;     -   a fourth rinsing tank for containing water; and     -   a warming and drying tank fed with hot air.

In these machines, the rinsing tank may have compartments between its upstream and downstream portion, realized by one or more transverse separating walls, traversed by the rotation axle of said rinsing tank, said rotation axle bearing a rotary structure in each compartment. The downstream compartment has an entry opening for its supply with fresh rinsing liquid, and the upstream compartment has an exit opening for the used rinsing liquid, and the separation walls have a passage for the rinsing liquid. These passages may take the form of overflow openings installed in the upper portions of these transverse separations.

In the installation according to this invention, the bottom of the container forms a storage basin for liquids. The capacity of the storage basin may be selected such as to be able to receive the totality of the volume of the liquids contained in the machine.

Preferably, the container contains a reservoir for the treatment liquid, a reservoir for the used treatment liquid, and a reservoir for used rinsing liquid.

Preferably, a device for retreating the used treatment and rinsing liquids is lodged within the container. According to a realization mode, the device for the retreatment of used liquids is an evaporator which retreats these used liquids by distillation and condensation.

Preferably, the container includes a gas scrubbing station. Especially a station for washing gases, connected to a water circuit and disposed in the space above the tanks.

Other characteristics and advantages of the invention will become evident to the one skilled in the art from the following description of a realization mode that is only given by way of non limiting example, and with reference to the attached drawings wherein:

FIG. 1 is an external perspective view of the entire installation according to the invention;

FIG. 2 is a perspective view of the installation shown in FIG. 1 but without conveyor chains and without the exterior walls of this installation;

FIG. 3 is a perspective view of the series of tanks of a machine according to the invention and showing their rotary structures;

FIG. 4 is a perspective view of the rotary structure of the electrolytic treatment tank;

FIG. 5 is a perspective view of the transfer device of the machine according to FIG. 2;

FIG. 6 is an enlarged perspective view that shows the upstream extremity of the rotary structure of the treatment tank according to FIG. 3, and its electrical connector; and

FIG. 7 is an enlarged perspective view that shows the downstream extremity of the rotary structure of the drying tank and the motor that drives the axle.

To FIGS. 1 and 2 illustrate an installation for the surface treatment of metallic parts according to this invention, in the present case for anodizing aluminum parts; the process requires the successive use of an electrolytic solution and a rinsing liquid.

FIG. 1 is a perspective view showing the exterior of the installation 700. All portions using fluids are disposed within a container 701 which is placed on a storage basin 702. A door 703 shown at the right in FIG. 1 gives access to the interior of the container 701. An air inlet 704 of a turbine is disposed on the front side of the container 701. A rectifier block 705 for the supply of the machine within the container 701 with direct current is arranged outside the container and shown at the left in FIG. 1. The raw parts that are to be anodized have been fastened before on supporting boxes (a process step that is not shown in the Figures) and are placed onto the left conveyor band 706 and are transported to the inlet of the container through an opening 707 whose dimensions are reduced as far as possible in order to reduce emanations from the container. The supporting boxes containing the anodized parts are taken up through a similar opening 708 at the outlet of the container by the conveyor band 709 shown at the right in FIG. 1, and then unloaded for being transported to a downstream use. This kind of conveyor band is known as such to the one skilled in the art. The supporting boxes 850, 851 that are loaded with parts are illustrated in all Figures by simple rectangular parallelepipeds only which are to show their external space requirement. Some examples of such supporting boxes are described in detail in patent No. EP-1 433 537 in the name of the Applicant and whose disclosure is incorporated into the present document by reference.

FIG. 2 is a perspective view of the interior of the container 701 shown in FIG. 1, showing an access catwalk 710 and the storage basin 702, on which are disposed the liquid tanks 500, 600, a group of devices 300, 400 for the treatment of the fluids and which will be described later, and a machine 1 for the surface treatment according to the invention.

The treatment machine 1 comprises a group 100 of tanks, a group of rotary structures 800, and a transfer device 200. As can be seen in FIGS. 2 and 3, the tanks 100 are disposed in series and are contiguous. A transfer device 200 which will be described later, is arranged above the group 100 formed by the tanks. The transfer device is suspended on three traverses 711 fastened at an armature (not shown in FIG. 2 for sake of clarity) of the container 701.

FIG. 3 is a perspective view of the three tanks 101, 102, 103 that constitute the series of tanks 100 in FIG. 2, and shows the disposition of the rotary structures loaded with supporting boxes in the tanks. The unit formed by the three tanks includes from upstream to downstream and from the left to the right in FIGS. 2 and 3:

-   -   an electrolytic treatment tank 101 in which are arranged         laterally on both sides two metal plates 104, 105 that form two         electrodes which constitute in this case the cathode;     -   a rinsing tank 102 with compartments between its upstream         portion and its downstream portion, formed by two transverse         separating walls 106 and 107, the downstream compartment 108         having an entry for the supply with fresh rinsing liquid, the         upstream compartment 110 having an exit for used rinsing liquid,         and the separating walls having in their upper portions overflow         openings;     -   a warming and drying tank 103 supplied with hot air by a turbine         111 via a conduct 112.

FIG. 4 is an enlarged view of the rotary structure 801 of the electrolytic treatment tank 101. The rotary structure comprises an axle 810 which is mounted horizontally for rotation and is suspended between bearings disposed in the upstream wall and the downstream wall of the corresponding tank. The axles 810, 820 and 830 of the three tanks 101, 102 and 103 are aligned with each other and fastened at their ends so that a unique common axle 840 is formed together that traverses the entire machine and is composed of the three axle segments 810, 820 and 830, An electric motor 805 is fastened to the terminal downstream wall of the drying tank 103, that drives by a direct drive the combined axle 840 and thus the rotary structures of the tanks 101, 102 and 103.

The axle segment 810 of the electrolytic treatment tank 101 is connected to the axle segment 820 of the rinsing tank 102 through an element made of an electrically insulating material. This axle segment 810 bears at its other extremity that goes beyond the upstream wall of the electrolytic treatment tank, this axle segment 810 bearing a rotary connector 804 comprising three rolls which rotate in the interior and are in contact with a contact cylinder 806 which is connected to the rectifier block 705 that constitutes the device for supply with direct current.

As can be seen in FIGS. 3, 4, 6 and 7, each rotary structure comprises several transverse plates 807, 808, 812 having an essential polygonal contour, that are mounted perpendicularly on the corresponding axle segments 810, 820 and 830 and are interlocked for rotation of the combined axle 840, see, for example, the reference 819. Pairs of longitudinal slide rails 809, 811 are mounted on the periphery of these transverse plates parallel to the rotation axle; their dimensions and distances are adapted to receiving the supporting boxes 850, 851 such as those already mentioned above. In the realization mode illustrated in FIGS. 3, 4, 6 and 7, the transverse plates 807, 808 and 812 support four pairs of slide rails 809, 811 disposed at 90° with respect to each other. The transverse plates 807, 808 and 812 may comprise cut-outs 817 and 818 in order to reduce the weight of the unit composed of a rotary structure and, in the case of plate 812 in the drying tank 103, for rendering easier the passage of the air flow. As can be seen in FIG. 3, each slide rail of the electrolytic treatment tank 101 is aligned with a slide rail of the tanks situated downstream so that the transfer of the supporting boxes from one tank to the next one by sliding along said slide rails is allowed. The alignment of the position of the slide rails is effected during the assembly of the machine and during the connection of the axle segments, and this procedure eliminates from the beginning later synchronization problems.

In the electrolytic treatment tank 101 as shown in FIG. 3, the slide rails 809, 811 are continuous from upstream to downstream of the tank. In contrast, the slide rails in the rinsing tank 102 are subdivided into three sections 814, 815 and 816 at short distances and aligned, each section of the slide rails being fastened on a pair of transverse plates 821, 822, the three rotary substructures created in such a manner being separated from each other by the two separating walls 106, 107 of the rinsing tank 102.

In the warming tank shown in FIG. 3, the slide rails 823, 824 are also segmented into two sections, each of these sections being fastened on a pair of transverse plates 812, 825, but the two rotary substructures thus created in this tank are not separated from each other by any compartment means.

The slide rails bear resilient contact plots 813 whose positions and distances correspond to the length of the supporting boxes 850, 851 and to the compartments 108, 109, 110 of the rinsing tank 102, thus allowing to withhold said supporting boxes at a predetermined longitudinal position on the slide rails during the rotation movements, and the sliding of the supporting boxes is allowed under the action of the transfer device between two rotation movements only.

The machine according to the invention comprises a transfer device 200 whose mounting position above the series of tanks 100 is shown in FIG. 2. Its constituting elements are shown in FIG. 5. It is synchronized with the driving device 805 of the machine axle. It includes a group of grasping elements of the supporting boxes that are temporarily situated in their upper position on said rotary structures. The transfer device effects a simultaneous transfer movement of all supporting boxes 850, 851 which are in their upper position, each support 850 in high position taking, under the effect of the said transfer movement, the place that has been occupied by the supporting box 851 immediately downstream in its high position before that transfer movement.

As it is shown in FIG. 5, the grasping elements for the supporting boxes include a horizontal shaft 201 that extends lengthwise above the series of tanks 100, and a group of arms 202, 205 mounted perpendicularly on said shaft 201, each arm bearing at its free extremity two pins 203, 204 that are oriented perpendicularly to the arm, the distance between two pins 203, 204 of the same arm 202 corresponding to the distance that separates two successive supporting boxes in their upper position, and the distance between two adjacent arms 202, 205 corresponding to the length of a supporting box. The length of the arms 202, 205 and their emplacement on the shaft 201 can be adjusted, and the height of the pins 203, 204 is also adjustable. Thus, the transfer device can be positioned and adjusted in such a manner that it can take up each supporting box 850, 851 simultaneously from the front and from behind, possible defects of the geometry of the rotary structures being compensated, and the reliability of the whole system is improved.

As it is shown in FIG. 5, the transfer device 200 comprises means for an alternating horizontal displacement between upstream and downstream positions of the shaft 201 and thus of the group of said grasping elements, and takes the form of a driven pinion and a toothed rack. The pinion 206 is fastened to a frame and a slide rail 208 that is fastened by traverses 711 to the armature bearing the device, and meshes with said rack mounted on a slider block 207; this slider block 207 being in turn fastened to the shaft 201, the stroke of said alternating displacing means being equal to the distance between two successive emplacements of supporting boxes at their high position.

The transfer device 200 comprises also a system for the release of said grasping elements, including a driving motor 210 driving a unique group 209 composed of a connecting rod and a crank, this latter driving the alternating pivoting of the shaft 201 and thus of the arms 202, 205, and this swinging motion engages and disengages simultaneously the pins 203, 204 of all supporting boxes that are in high position and allows the rotary structure 800 to rotate. The arms 202 will pivot between a lowered position near to the horizontal plane and a heightened position. The shaft 201, the slider block 207 and the slide rail 208 are thus parallel with the supporting boxes but laterally offset with respect to the slide rail pairs in high position. When the grasping system is in its heightened position, the transfer device makes a translation of the shaft 201 in upstream direction thanks to the system of pinion and rack, and it will take the former position for the following transfer movement.

In a method for anodizing in using the treatment machine 1 that has been described above, the electrolytic treatment tank 101 is filled for example with a sulfuric acid solution and allows to realize the anodizing of aluminum parts attached to supporting boxes. For this kind of treatment, the tank 101 comprises two metal plates that form the cathode and are disposed on both sides of the rotary structure 801 near the lateral walls of the tank, the rotary structure being supplied with an electric current having the opposed polarity with respect to the electrodes, said electric current being transmitted to the parts to be treated via, successively, the axle 810, the transverse plates 807, 808, the slide rails 809, 811 and the supporting boxes 850. During the implementation of the method in the treatment installation according to the invention, each part is immerged in the tank 101 by having it undergo, according to the realization mode shown in the Figures, four complete revolutions in such a manner that air bubbles and air pouches which may be formed in the interior of the tank in contact with the parts, are eliminated, thus allowing the treatment liquid to integrally treat the surface of the parts and rendering the treatment perfectly homogeneous.

Thus, the supporting boxes which hold the parts not yet treated, brought about by the conveyor chain 706, are engaged by horizontal displacement at the upstream extremity of the pair of slide rails not immerged and situated momentarily at the summit of the rotary structure 801, each supporting box being positioned lengthwise on the upper pair of slide rails thanks to the transfer device 200 which cooperates with the resilient contact devices 813 of the pair of slide rails. The totality of the treatment machine shown in FIGS. 2 through 5 operates by sequenced, clocked and synchronized movements. According to the illustrated realization mode, the rotary structure 801 comprises on its periphery four pairs of slide rails 809, 811 oriented at 90° with respect to each other and provided for receiving the supporting boxes 850, 851 which hold the parts to be treated. After each rotation by 90° , all supporting boxes 850, 851 momentarily disposed at their emerged, high position, undergo a longitudinal translation whose length corresponds to the distance between two adjacent supporting boxes whereas the other supporting boxes which are immerged, are not displaced on the slide rails. As shown in FIGS. 3 and 4, each supporting box is rotated between two translations by a complete revolution of 360° subdivided into four rotations by 90° each. Each supporting box is thus immerged during nearly four complete rotations within the liquid contained in the electrolytic treatment tank 101 with the exception of the upper portion during each rotation where the supporting box is situated momentarily out of the liquid for allowing the emplacement, the advance, the transfer and the recovery of the parts.

At each sequence, namely after every rotation by 90° , one supporting box containing parts that have been treated by electrolysis, is transferred from the electrolytic treatment tank 101 onto the rotary structure 802 of the first compartment 110 of the rinsing tank 102 and is then immerged into the rinsing liquid during the next rotation, in order to make a complete revolution. Then, it is transported into the second compartment 109, makes a rotation of 360° therein, and then passes into the third compartment 108 where it makes a final rotation of 360° before being transported into the warming tank 103. The rinsing tank is continuously supplied with rinsing liquid. This rinsing liquid enters first into the third compartment 103 of the rinsing tank, then flows into the second compartment 109 through the opening in the separation wall 107 between these two compartments, and then into the first compartment 110 before being evacuated into a storing tank for used liquid. The one skilled in the art will have understood that, thanks to this arrangement, the rinsing operation is executed as a kind of “countercurrent washing” according to the terminology of the field of chemical separations.

In the third tank 103 which contains a rotary structure 803 whose length is equivalent to two positions of the supporting boxes, these latter make two complete revolutions before being engaged by the transfer device 200 against the conveyor chain 709 downstream the installation. This warming tank does not contain any liquid but is traversed by a hot air flow supplied by the turbine 111, 112. Thanks to the rotation of the parts in the tank 103 with respect to the direction of the air flow, the droplets of the rinsing liquid are efficiently eliminated from the walls of the parts, even if the parts have cavities and hollow portions. Such a rotation is not provided in conventional drying tunnels.

The air that is charged with humidity and exits the drying tank 103, is collected and mixed with the air charged with vapors sucked off by the hood 401 disposed above the oxidation tank 101 and above the rinsing tank 102 and then treated in a block 402 containing a fan and a gas scrubber, installed within the container 701. The hourly aspiration capacity of the hood 401 and the fan and scrubber block 402 may be selected to be 2 to 8 times, typically 4 times, the inner volume of the container. This kind of apparatus is as such well known to the one skilled in the art of surface treatment. The air that exits from this gas collecting and scrubbing station 400 may be blown without any restriction into the surrounding atmosphere.

The water which exits from the gas scrubber is collected in an intermediate storage tank. This water is mixed with used rinsing liquids and retreated in the evaporator 300 which forms a small distillation-condensation unit. The distillate is recycled as a rinsing liquid. The residue that is composed of an acidic electrolyte solution is transferred to an intermediate storage tank and then mixed with fresh electrolyte.

The used electrolyte is also stored in an intermediate storage tank and then retreated in the evaporator; the distillate being combined with fresh electrolyte, and the distillation residue whose volume is small is stored for an external retreatment. Seen as a whole, the installation according to the invention only produces a small volume of rejections that cannot be treated in situ, and the installation can thus be used in a factory which does not have facilities of a plant for the electrochemical surface treatments.

Each supporting box that traverses the machine according to the invention makes a path that may globally be qualified as helical although it is in fact composed of a succession of rotations and translations. Furthermore, the path of each supporting box is composed of clocked sequences of these movements but the overall processing by treating a great number of supporting boxes should be considered as a continuous process. It is therefore possible to adjust the flow rate of the supplies of fluids, treatment liquids, rinsing liquids and air so as to operate an established continuous processing, the volumes and concentrations of the fluids in all tanks 100 of the series remaining constant. Therefore, the quality of the treated parts remains perfectly constant.

Furthermore, the quality of the air rejected by the gas scrubber installation remains also perfectly constant. The retreatment of the liquid effluents within the container can be executed as a continuous or a batchwise process thanks to the tanks 500, 600 that allow an intermediate storage.

EXAMPLES 1. Examples of Anodic Treatment of Aluminum Parts

The installation described above and whose group of tanks is illustrated in FIGS. 2 and 3, has especially been used to treat:

-   -   caps for cosmetic product bottles;     -   nuts for pressure indicators;     -   brake pistons;     -   gearbox casings;     -   derailleurs for bicycle hubs;     -   buckles for handbags;     -   supports for rain detectors on motorcars;     -   couplers for automatic gear boxes.

The container of this installation, shown in FIG. 1, had a length of about 5 meters whereas an installation according to the document WO 2008/035199 for executing the same treatment has a length of about 12 meters, the drying tunnel included.

2. Examples of Electroplating Treatments

An installation according to the invention has been used for electrolytic nickel plating, namely an electroplating method but not a conversion method, of steel parts for motor car manufacture. The parts had been degreased before in a solvent.

In order to carry out this process, the installation uses 9 tanks comprising a total of 14 compartments:

-   -   the first tank is a tank for sulfophosphoric pickling;     -   the second tank is a tank for double rinsing with demineralized         water;     -   the third tank is a tank for electro-anodic degreasing with the         use of sodium hydroxide;     -   the fourth tank is a tank for double rinsing containing         demineralized water;     -   the fifth tank is a tank for sulfuric depassivation;     -   the sixth tank is a tank for double rinsing containing         demineralized water;     -   the seventh tank is a tank for nickel plating using nickel         sulfamate where the actual electroplating takes place; the tank         contains a nickel sulfate solution heated to 60° C. The tank is         equipped with two nickel plates forming the electrodes and         disposed on both sides of the rotary structure of this tank. The         section of the axle of the rotary structure of this tank is         electrically insulated from the sections of this axle situated         upstream and downstream;     -   the eighth tank is a tank for triple rinsing comprising a         rinsing called “dead rinsing”, the three compartments containing         demineralized water; and     -   the ninth tank is a warming and drying tank supplied with hot         air.

The intensity of the electric current that is applied to the electrodes and the parts in the nickel plating tank is about 0.5 A/square decimeter. The nickel deposition formed on the surface of the parts presents an essentially constant thickness of 3 to 5 micrometers. The rate of rejection of defective parts is lower than 0.1%.

It will be noted that all rinsing tanks comprise two or three compartments for washing and rinsing the parts by countercurrent with the purpose of eliminating as completely as possible the residues of the active solutions in the treatment tank situated upstream and for avoiding a pollution of active solutions in the downstream treating tank.

3. Examples of Treatments That Can be Executed in the Machine and the Installation According to the Invention

a) Electrolytic treatments

Cathodic electrolytic coatings of:

-   -   nickel Watts and nickel sulfamates     -   zinc and zinc-nickel     -   tin     -   copper     -   noble metals (silver, gold, rhodium, platinum metals family . .         . )

Anodic transformations:

-   -   aluminum oxidation     -   titanium oxidation . . .

Paints:

-   -   chemical     -   anaphoresis     -   cataphoresis

Electrolytic polishing of stainless steels

b) Electroplating of plastics

-   -   copper plating on plastics     -   nickel plating on plastics     -   chromium plating on plastics

c) Various chemical treatments such as:

-   -   transformation by chemical deburing and/or mirror finishing of         aluminum alloy and other substrates     -   chemical transformations such as steel and aluminum passivation     -   chemical stripping of titanium alloys (with nitro hydrofluoric         mixtures)     -   chemical nickeling of current steels.

Of course, the above listing of treatments is not exhaustive and is given as non-limiting examples only. The one skilled in the art will know how to adapt, for every concrete application, the number of tanks and of compartments of the machine as well as the equipment provided for the treatment of the effluents.

Of course, the invention is not limited to the realization modes that have been described above, but it comprises numerous technical variants and their combinations:

-   -   Thus, FIG. 4 shows a rotary structure comprising 4 fastening         positions for the boxes. This number may be a different one.         With only 2 fixation positions for example, each transverse         plate may be replaced by two arms.     -   The supporting boxes mentioned above are particularly well         adapted to the treatment of series of parts having small         dimensions. In the case of a unit for the treatment of parts         having large but invariable dimensions, these parts may directly         be fastened on the rotary structures and through the         intermediate of other fastening means than sliders.     -   The axles of the rotary structures of two successive tanks may         be connected through gears which put them into rotary         interlocking condition without compulsory alignment.     -   The tank entity 100 may comprise several tanks separately         constructed and then installed in series. It may also be         realized by means of a tank having a great length and divided by         parting walls to form a plurality of compartments providing         different functions. 

1-16. (canceled)
 17. Machine for the surface treatment of metallic parts by the immersion of said parts into at least one treatment liquid contained in a treatment tank, said machine including a plurality of tanks arranged in series, and a transfer device of the parts between said tanks, said tanks each comprising a rotary structure mounted on a rotation axle and capable of receiving said parts, said parts being submerged in said treatment liquid by a rotational movement of the rotary structure of the treatment tank, selected in such a manner that air bubbles that may be formed during the immersion of said parts, are chased away from the surfaces of said parts, wherein said rotation axles of said rotary structures in the series of tanks are in rotary interlock condition and are driven by a common driving device.
 18. Machine according to claim 17, wherein said tanks that are arranged in series are contiguous, and that said rotation axles of said rotary structures of said tank series are aligned and assembled in such a manner that a common rotation axle is formed that traverses the whole machine.
 19. Machine according to claim 17, wherein said common driving device includes an electric motor providing a direct drive of said rotation axles, in particular an electric motor disposed at a first extremity of said series of tanks.
 20. Machine according to claim 17, wherein the rotation axle of said treatment tank is electrically insulated from other axle portions, in that the rotary structure of said treatment tank is connected to an electric generator via the intermediate of the rotation axle of said treatment tank.
 21. Machine according to claim 19, wherein the rotation axle of said treatment tank is electrically insulated from other portions of the axle, in that the rotary structure of said treatment tank is connected to an electric generator via the intermediate of the rotation axle of said treatment tank by means of a rotary connector disposed at a second extremity of said series of tanks.
 22. Machine according to claim 17, wherein said rotary structures are equipped with retaining devices capable of temporarily retaining supports for parts, supports whose dimensions are adapted to said retaining devices during the rotary movements of said rotary structures, the retaining devices being capable of allowing a transfer movement of supports between two rotation movements under the action of said transfer device, said supports bearing fastening means adapted to hold said metallic parts during said surface treatment.
 23. Machine according to claim 22, wherein said retaining devices include slide rails installed parallel to said rotation axles of said rotary structures, each one of said slide rails of a tank being aligned to a slide rail of the tanks that is disposed respectively upstream and downstream so that the transfer of said supports of a tank to the following one is allowed under the action of said transfer device in sliding along said slide rails, and in that at least a portion of said slide rails bears resilient contact devices allowing to hold said supports in a predetermined position on said slide rails during said rotation movements and the sliding of the supports under the action of the transfer device.
 24. Machine according to claim 22, wherein it includes a transfer device disposed above said tanks and synchronized with the driving device of the machine, comprising grasping elements, grasping the supports which have temporarily been raised to their uppermost position on said rotary structures, means for releasing said grasping elements from said supports in upper position, and means for displacing said grasping elements in an alternating upstream-downstream manner, the stroke of said alternating displacement means being equal to the distance between two successive emplacements of supports in their upper position, said transfer device making a simultaneous transfer movement of said supports in their upper position, each support in upper position taking, under the effect of said transfer movement, the position that was occupied before said transfer movement by the immediately downstream support in upper position.
 25. Machine according to claim 24, wherein said grasping elements include a shaft that extends above said series of tanks, and a group of arms mounted on said shaft, each arm bearing at its free end two pins distant and perpendicular with respect to the arm, the distance between these two pins of the same arm corresponding to the distance that separates two successive supports in upper position, the distance between two arms corresponding to the length of one said support, in that said transfer device includes a group composed of a driving pinion and a toothed rack, said pinion being fastened to a frame and a slide rail and meshing with said toothed rack that is fastened to a slider block, said slider block bearing said shaft, and a motorized unit formed by a connecting rod and a crank for driving said shaft in order to simultaneously release said grasping elements of all supports in upper position.
 26. Machine according to claim 17, destined for anodizing metallic parts, including from upstream to downstream: an oxidation treatment tank for containing an electrolytic treatment liquid, said oxidation tank comprising at least one electrode serving as cathode, said rotary structure serving as an anode, a rinsing tank for containing a rinsing liquid, a warming tank for being fed with hot air.
 27. Machine according to claim 17, destined for anodizing metallic parts, including from upstream to downstream: an oxidation treatment tank for containing an electrolytic treatment liquid, said oxidation tank comprising two cathodes disposed on both sides of the rotary structure of the treatment tank, said rotary structure serving as an anode, a rinsing tank for containing a rinsing liquid, a warming tank for being fed with hot air.
 28. Machine according to claim 17, for the electrolytic nickel plating of steel parts, including from upstream to downstream: a pickling tank for containing a pickling liquid; a first rinsing tank for containing water; a degreasing tank for containing an aqueous degreasing solution; a second rinsing tank for containing water; a depassivation tank for containing a sulfuric depassivation liquid; a third rincing tank for containing water a nickel plating tank for the actual electroplating, for containing a nickel sulfate solution and equipped with electrode forming nickel plates, especially two anodes disposed on both sides of the rotary structure of said nickel plating tank; a fourth rinsing tank for containing water; and a warming and drying tank fed with hot air.
 29. Machine according to claim 26, wherein said rinsing tank is subdivided into compartments between their upstream and downstream portion by at least one transverse separating wall and traversed by the rotation axle of said rinsing tank, said rotation axle bearing a rotary structure within each compartment, the downstream compartment including an entry for the introduction of fresh rinsing liquid, the upstream compartment including an exit for the used rinsing liquid, said separation wall comprising an opening allowing the passage of the rinsing liquid from downstream to upstream.
 30. Installation for the surface treatment of metallic parts, wherein it comprises the machine according to claim 17, lodged in a container containing confinement and retreating means for the fluids flowing out of said machine.
 31. Installation according to claim 30, wherein the bottom of said container forms a liquid storage basin, especially in that the capacity of said storage basin is selected such that it may receive the totality of the volume of all liquids that are present in said machine.
 32. Installation according to claim 31, wherein said container includes a basin for the treatment liquid, a basin for the used treatment liquid, and a basin for used rinsing liquid.
 33. Installation according to claim 32, wherein a device for the retreating of the used treatment and rinsing liquids is lodged in the interior of the container.
 34. Installation according to claim 33, wherein the device for the retreatment of the used liquids is an evaporator where said used liquids are retreated by distillation and condensation.
 35. Installation according to claim 30, wherein the container includes a gas scrubbing station installed above the tank outlets.
 36. Installation according to claim 35, wherein said gas scrubbing station is connected to a water circuit. 